Bump to v21.1 re: repo management changes, etc.

* End package releases on anaconda.org GoMSS-Nowcast channel.
  Final release there was v19.2

* Change name of Git repository default branch from ``master`` to ``main``.

* Add support for exception logging to Sentry (https://sentry.io) with client
  DSN URL from SENTRY_DSN environment variable; does nothing if SENTRY_DSN
  does not exist, is empty, or is not recognized by Sentry.

* Change continuous integration from Bitbucket pipeline to GitHub Actions
  workflow. CI reports are at https://github.com/43ravens/NEMO_Nowcast/actions
  Unit test coverage report visualization is at
  https://codecov.io/gh/43ravens/NEMO_Nowcast

* Migrate from Mercurial on Bitbucket to Git on GitHub due to Bitbucket's
  decision to terminate support for Mercurial.
  Repository is now at https://github.com/43ravens/NEMO_Nowcast

* Expose ``nemo_nowcast.cli.arrow_date()`` function for use by packages like
  SalishSeaNowcast that use NEMO_Nowcast CLI elements.

* Change process manager from `circus`_ to `supervisor`_ because ``circus`` has
  dependency version pins that prevent moving to newer versions of Python
  and 0mq (and probably other packages).
  ``cirucs`` does not appear to be being actively maintained any more.
  ``supervisor`` has fewer dependencies, provides all of the functionality
  that we need, and is being actively maintained.

  .. _supervisor: http://supervisord.org/

__pkg_metadata__.py

@@ -16,5 +16,5 @@
 """
 PROJECT = "NEMO_Nowcast"
 DESCRIPTION = "NEMO ocean model nowcast framework"
-VERSION = "21.1.dev0"
+VERSION = "21.1"
 DEV_STATUS = "5 - Production/Stable"

docs/CHANGES.rst

@@ -2,8 +2,13 @@
 Change Log
 **********
 
-v21.1.dev0 (unreleased)
-=======================
+v21.1 (2021-03-03)
+==================
+
+* End package releases on anaconda.org GoMSS-Nowcast channel.
+  Final release there was v19.2
+
+* Change name of Git repository default branch from ``master`` to ``main``.
 
 * Add support for exception logging to Sentry (https://sentry.io) with client DSN URL
   from SENTRY_DSN environment variable; does nothing if SENTRY_DSN does not exist,